Firms’ activities are inextricably linked to the grand societal challenges confronting humanity, as articulated by the UN Sustainable Development Goals, both as contributors to the creation of and as critical actors in attempts to address grand societal challenges. Yet little is known about the societal impact of small and medium-sized enterprises' (SME) micro-level CSR initiatives. This systematic review, of 226 small business social responsibility (SBSR) studies, assesses the evidence for SMEs’ micro-level societal impacts and the primary stakeholders in these outcomes. To do so a three-part definition of societal impacts is adopted, distinguishing between social inputs, processes and benefits. Evidence shows that SMEs’ societal input impacts are primarily related to philanthropic, community involvement, sustainable employment, sponsorship and responding to customer needs CSR initiatives. SMEs’ societal process impacts are most clearly related to philanthropic, sustainable employment and community involvement CSR initiatives. While SMEs’ societal benefit impacts are least addressed and most clearly related to philanthropic and sustainable employment CSR initiatives. This suggests SME managers have the potential to significantly increase their societal impact, by raising their awareness and understanding of the nature of their CSR initiatives and their primary local stakeholders, namely the local community, employees and consumers/customers.